[deb_ffmpeg.git] / ffmpeg / libavcodec / vp56.h

/*
 * Copyright (C) 2006  Aurelien Jacobs <aurel@gnuage.org>
 *
 * This file is part of FFmpeg.
 *
 * FFmpeg is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * FFmpeg is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with FFmpeg; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

/**
 * @file
 * VP5 and VP6 compatible video decoder (common features)
 */

#ifndef AVCODEC_VP56_H
#define AVCODEC_VP56_H

#include "get_bits.h"
#include "hpeldsp.h"
#include "bytestream.h"
#include "h264chroma.h"
#include "videodsp.h"
#include "vp3dsp.h"
#include "vp56dsp.h"

typedef struct vp56_context VP56Context;

typedef enum {
    VP56_FRAME_NONE     =-1,
    VP56_FRAME_CURRENT  = 0,
    VP56_FRAME_PREVIOUS = 1,
    VP56_FRAME_GOLDEN   = 2,
    VP56_FRAME_GOLDEN2  = 3,
} VP56Frame;

typedef enum {
    VP56_MB_INTER_NOVEC_PF = 0,  /**< Inter MB, no vector, from previous frame */
    VP56_MB_INTRA          = 1,  /**< Intra MB */
    VP56_MB_INTER_DELTA_PF = 2,  /**< Inter MB, above/left vector + delta, from previous frame */
    VP56_MB_INTER_V1_PF    = 3,  /**< Inter MB, first vector, from previous frame */
    VP56_MB_INTER_V2_PF    = 4,  /**< Inter MB, second vector, from previous frame */
    VP56_MB_INTER_NOVEC_GF = 5,  /**< Inter MB, no vector, from golden frame */
    VP56_MB_INTER_DELTA_GF = 6,  /**< Inter MB, above/left vector + delta, from golden frame */
    VP56_MB_INTER_4V       = 7,  /**< Inter MB, 4 vectors, from previous frame */
    VP56_MB_INTER_V1_GF    = 8,  /**< Inter MB, first vector, from golden frame */
    VP56_MB_INTER_V2_GF    = 9,  /**< Inter MB, second vector, from golden frame */
} VP56mb;

typedef struct VP56Tree {
  int8_t val;
  int8_t prob_idx;
} VP56Tree;

typedef struct VP56mv {
    DECLARE_ALIGNED(4, int16_t, x);
    int16_t y;
} VP56mv;

#define VP56_SIZE_CHANGE 1

typedef void (*VP56ParseVectorAdjustment)(VP56Context *s,
                                          VP56mv *vect);
typedef void (*VP56Filter)(VP56Context *s, uint8_t *dst, uint8_t *src,
                           int offset1, int offset2, int stride,
                           VP56mv mv, int mask, int select, int luma);
typedef void (*VP56ParseCoeff)(VP56Context *s);
typedef void (*VP56DefaultModelsInit)(VP56Context *s);
typedef void (*VP56ParseVectorModels)(VP56Context *s);
typedef int  (*VP56ParseCoeffModels)(VP56Context *s);
typedef int  (*VP56ParseHeader)(VP56Context *s, const uint8_t *buf,
                                int buf_size);

typedef struct VP56RangeCoder {
    int high;
    int bits; /* stored negated (i.e. negative "bits" is a positive number of
                 bits left) in order to eliminate a negate in cache refilling */
    const uint8_t *buffer;
    const uint8_t *end;
    unsigned int code_word;
} VP56RangeCoder;

typedef struct VP56RefDc {
    uint8_t not_null_dc;
    VP56Frame ref_frame;
    int16_t dc_coeff;
} VP56RefDc;

typedef struct VP56Macroblock {
    uint8_t type;
    VP56mv mv;
} VP56Macroblock;

typedef struct VP56Model {
    uint8_t coeff_reorder[64];       /* used in vp6 only */
    uint8_t coeff_index_to_pos[64];  /* used in vp6 only */
    uint8_t vector_sig[2];           /* delta sign */
    uint8_t vector_dct[2];           /* delta coding types */
    uint8_t vector_pdi[2][2];        /* predefined delta init */
    uint8_t vector_pdv[2][7];        /* predefined delta values */
    uint8_t vector_fdv[2][8];        /* 8 bit delta value definition */
    uint8_t coeff_dccv[2][11];       /* DC coeff value */
    uint8_t coeff_ract[2][3][6][11]; /* Run/AC coding type and AC coeff value */
    uint8_t coeff_acct[2][3][3][6][5];/* vp5 only AC coding type for coding group < 3 */
    uint8_t coeff_dcct[2][36][5];    /* DC coeff coding type */
    uint8_t coeff_runv[2][14];       /* run value (vp6 only) */
    uint8_t mb_type[3][10][10];      /* model for decoding MB type */
    uint8_t mb_types_stats[3][10][2];/* contextual, next MB type stats */
} VP56Model;

struct vp56_context {
    AVCodecContext *avctx;
    H264ChromaContext h264chroma;
    HpelDSPContext hdsp;
    VideoDSPContext vdsp;
    VP3DSPContext vp3dsp;
    VP56DSPContext vp56dsp;
    uint8_t idct_scantable[64];
    AVFrame *frames[4];
    uint8_t *edge_emu_buffer_alloc;
    uint8_t *edge_emu_buffer;
    VP56RangeCoder c;
    VP56RangeCoder cc;
    VP56RangeCoder *ccp;
    int sub_version;

    /* frame info */
    int golden_frame;
    int plane_width[4];
    int plane_height[4];
    int mb_width;   /* number of horizontal MB */
    int mb_height;  /* number of vertical MB */
    int block_offset[6];

    int quantizer;
    uint16_t dequant_dc;
    uint16_t dequant_ac;

    /* DC predictors management */
    VP56RefDc *above_blocks;
    VP56RefDc left_block[4];
    int above_block_idx[6];
    int16_t prev_dc[3][3];    /* [plan][ref_frame] */

    /* blocks / macroblock */
    VP56mb mb_type;
    VP56Macroblock *macroblocks;
    DECLARE_ALIGNED(16, int16_t, block_coeff)[6][64];

    /* motion vectors */
    VP56mv mv[6];  /* vectors for each block in MB */
    VP56mv vector_candidate[2];
    int vector_candidate_pos;

    /* filtering hints */
    int filter_header;               /* used in vp6 only */
    int deblock_filtering;
    int filter_selection;
    int filter_mode;
    int max_vector_length;
    int sample_variance_threshold;

    uint8_t coeff_ctx[4][64];              /* used in vp5 only */
    uint8_t coeff_ctx_last[4];             /* used in vp5 only */

    int has_alpha;

    /* upside-down flipping hints */
    int flip;  /* are we flipping ? */
    int frbi;  /* first row block index in MB */
    int srbi;  /* second row block index in MB */
    int stride[4];  /* stride for each plan */

    const uint8_t *vp56_coord_div;
    VP56ParseVectorAdjustment parse_vector_adjustment;
    VP56Filter filter;
    VP56ParseCoeff parse_coeff;
    VP56DefaultModelsInit default_models_init;
    VP56ParseVectorModels parse_vector_models;
    VP56ParseCoeffModels parse_coeff_models;
    VP56ParseHeader parse_header;

    /* for "slice" parallelism between YUV and A */
    VP56Context *alpha_context;

    VP56Model *modelp;
    VP56Model model;

    /* huffman decoding */
    int use_huffman;
    GetBitContext gb;
    VLC dccv_vlc[2];
    VLC runv_vlc[2];
    VLC ract_vlc[2][3][6];
    unsigned int nb_null[2][2];       /* number of consecutive NULL DC/AC */
};


int ff_vp56_init(AVCodecContext *avctx, int flip, int has_alpha);
int ff_vp56_init_context(AVCodecContext *avctx, VP56Context *s,
                          int flip, int has_alpha);
int ff_vp56_free(AVCodecContext *avctx);
int ff_vp56_free_context(VP56Context *s);
void ff_vp56_init_dequant(VP56Context *s, int quantizer);
int ff_vp56_decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
                         AVPacket *avpkt);


/**
 * vp56 specific range coder implementation
 */

extern const uint8_t ff_vp56_norm_shift[256];
void ff_vp56_init_range_decoder(VP56RangeCoder *c, const uint8_t *buf, int buf_size);

static av_always_inline unsigned int vp56_rac_renorm(VP56RangeCoder *c)
{
    int shift = ff_vp56_norm_shift[c->high];
    int bits = c->bits;
    unsigned int code_word = c->code_word;

    c->high   <<= shift;
    code_word <<= shift;
    bits       += shift;
    if(bits >= 0 && c->buffer < c->end) {
        code_word |= bytestream_get_be16(&c->buffer) << bits;
        bits -= 16;
    }
    c->bits = bits;
    return code_word;
}

#if   ARCH_ARM
#include "arm/vp56_arith.h"
#elif ARCH_X86
#include "x86/vp56_arith.h"
#endif

#ifndef vp56_rac_get_prob
#define vp56_rac_get_prob vp56_rac_get_prob
static av_always_inline int vp56_rac_get_prob(VP56RangeCoder *c, uint8_t prob)
{
    unsigned int code_word = vp56_rac_renorm(c);
    unsigned int low = 1 + (((c->high - 1) * prob) >> 8);
    unsigned int low_shift = low << 16;
    int bit = code_word >= low_shift;

    c->high = bit ? c->high - low : low;
    c->code_word = bit ? code_word - low_shift : code_word;

    return bit;
}
#endif

#ifndef vp56_rac_get_prob_branchy
// branchy variant, to be used where there's a branch based on the bit decoded
static av_always_inline int vp56_rac_get_prob_branchy(VP56RangeCoder *c, int prob)
{
    unsigned long code_word = vp56_rac_renorm(c);
    unsigned low = 1 + (((c->high - 1) * prob) >> 8);
    unsigned low_shift = low << 16;

    if (code_word >= low_shift) {
        c->high     -= low;
        c->code_word = code_word - low_shift;
        return 1;
    }

    c->high = low;
    c->code_word = code_word;
    return 0;
}
#endif

static av_always_inline int vp56_rac_get(VP56RangeCoder *c)
{
    unsigned int code_word = vp56_rac_renorm(c);
    /* equiprobable */
    int low = (c->high + 1) >> 1;
    unsigned int low_shift = low << 16;
    int bit = code_word >= low_shift;
    if (bit) {
        c->high   -= low;
        code_word -= low_shift;
    } else {
        c->high = low;
    }

    c->code_word = code_word;
    return bit;
}

// rounding is different than vp56_rac_get, is vp56_rac_get wrong?
static av_always_inline int vp8_rac_get(VP56RangeCoder *c)
{
    return vp56_rac_get_prob(c, 128);
}

static int vp56_rac_gets(VP56RangeCoder *c, int bits)
{
    int value = 0;

    while (bits--) {
        value = (value << 1) | vp56_rac_get(c);
    }

    return value;
}

static int vp8_rac_get_uint(VP56RangeCoder *c, int bits)
{
    int value = 0;

    while (bits--) {
        value = (value << 1) | vp8_rac_get(c);
    }

    return value;
}

// fixme: add 1 bit to all the calls to this?
static av_unused int vp8_rac_get_sint(VP56RangeCoder *c, int bits)
{
    int v;

    if (!vp8_rac_get(c))
        return 0;

    v = vp8_rac_get_uint(c, bits);

    if (vp8_rac_get(c))
        v = -v;

    return v;
}

// P(7)
static av_unused int vp56_rac_gets_nn(VP56RangeCoder *c, int bits)
{
    int v = vp56_rac_gets(c, 7) << 1;
    return v + !v;
}

static av_unused int vp8_rac_get_nn(VP56RangeCoder *c)
{
    int v = vp8_rac_get_uint(c, 7) << 1;
    return v + !v;
}

static av_always_inline
int vp56_rac_get_tree(VP56RangeCoder *c,
                      const VP56Tree *tree,
                      const uint8_t *probs)
{
    while (tree->val > 0) {
        if (vp56_rac_get_prob_branchy(c, probs[tree->prob_idx]))
            tree += tree->val;
        else
            tree++;
    }
    return -tree->val;
}

// how probabilities are associated with decisions is different I think
// well, the new scheme fits in the old but this way has one fewer branches per decision
static av_always_inline int vp8_rac_get_tree(VP56RangeCoder *c, const int8_t (*tree)[2],
                                   const uint8_t *probs)
{
    int i = 0;

    do {
        i = tree[i][vp56_rac_get_prob(c, probs[i])];
    } while (i > 0);

    return -i;
}

// DCTextra
static av_always_inline int vp8_rac_get_coeff(VP56RangeCoder *c, const uint8_t *prob)
{
    int v = 0;

    do {
        v = (v<<1) + vp56_rac_get_prob(c, *prob++);
    } while (*prob);

    return v;
}

#endif /* AVCODEC_VP56_H */
Commit	Line	Data
2ba45a60 DM	1	/*
	2	* Copyright (C) 2006 Aurelien Jacobs <aurel@gnuage.org>
	3	*
	4	* This file is part of FFmpeg.
	5	*
	6	* FFmpeg is free software; you can redistribute it and/or
	7	* modify it under the terms of the GNU Lesser General Public
	8	* License as published by the Free Software Foundation; either
	9	* version 2.1 of the License, or (at your option) any later version.
	10	*
	11	* FFmpeg is distributed in the hope that it will be useful,
	12	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	13	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	14	* Lesser General Public License for more details.
	15	*
	16	* You should have received a copy of the GNU Lesser General Public
	17	* License along with FFmpeg; if not, write to the Free Software
	18	* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
	19	*/
	20
	21	/**
	22	* @file
	23	* VP5 and VP6 compatible video decoder (common features)
	24	*/
	25
	26	#ifndef AVCODEC_VP56_H
	27	#define AVCODEC_VP56_H
	28
	29	#include "get_bits.h"
	30	#include "hpeldsp.h"
	31	#include "bytestream.h"
	32	#include "h264chroma.h"
	33	#include "videodsp.h"
	34	#include "vp3dsp.h"
	35	#include "vp56dsp.h"
	36
	37	typedef struct vp56_context VP56Context;
	38
	39	typedef enum {
	40	VP56_FRAME_NONE =-1,
	41	VP56_FRAME_CURRENT = 0,
	42	VP56_FRAME_PREVIOUS = 1,
	43	VP56_FRAME_GOLDEN = 2,
	44	VP56_FRAME_GOLDEN2 = 3,
	45	} VP56Frame;
	46
	47	typedef enum {
	48	VP56_MB_INTER_NOVEC_PF = 0, /*< Inter MB, no vector, from previous frame /
	49	VP56_MB_INTRA = 1, /*< Intra MB /
	50	VP56_MB_INTER_DELTA_PF = 2, /*< Inter MB, above/left vector + delta, from previous frame /
	51	VP56_MB_INTER_V1_PF = 3, /*< Inter MB, first vector, from previous frame /
	52	VP56_MB_INTER_V2_PF = 4, /*< Inter MB, second vector, from previous frame /
	53	VP56_MB_INTER_NOVEC_GF = 5, /*< Inter MB, no vector, from golden frame /
	54	VP56_MB_INTER_DELTA_GF = 6, /*< Inter MB, above/left vector + delta, from golden frame /
	55	VP56_MB_INTER_4V = 7, /*< Inter MB, 4 vectors, from previous frame /
	56	VP56_MB_INTER_V1_GF = 8, /*< Inter MB, first vector, from golden frame /
	57	VP56_MB_INTER_V2_GF = 9, /*< Inter MB, second vector, from golden frame /
	58	} VP56mb;
	59
	60	typedef struct VP56Tree {
	61	int8_t val;
	62	int8_t prob_idx;
	63	} VP56Tree;
	64
65	typedef struct VP56mv {
66	DECLARE_ALIGNED(4, int16_t, x);
67	int16_t y;
68	} VP56mv;
69
70	#define VP56_SIZE_CHANGE 1
71
72	typedef void (VP56ParseVectorAdjustment)(VP56Context s,
73	VP56mv *vect);
74	typedef void (VP56Filter)(VP56Context s, uint8_t dst, uint8_t src,
75	int offset1, int offset2, int stride,
76	VP56mv mv, int mask, int select, int luma);
77	typedef void (VP56ParseCoeff)(VP56Context s);
78	typedef void (VP56DefaultModelsInit)(VP56Context s);
79	typedef void (VP56ParseVectorModels)(VP56Context s);
80	typedef int (VP56ParseCoeffModels)(VP56Context s);
81	typedef int (VP56ParseHeader)(VP56Context s, const uint8_t *buf,
82	int buf_size);
83
84	typedef struct VP56RangeCoder {
85	int high;
86	int bits; /* stored negated (i.e. negative "bits" is a positive number of
87	bits left) in order to eliminate a negate in cache refilling */
88	const uint8_t *buffer;
89	const uint8_t *end;
90	unsigned int code_word;
91	} VP56RangeCoder;
92
93	typedef struct VP56RefDc {
94	uint8_t not_null_dc;
95	VP56Frame ref_frame;
96	int16_t dc_coeff;
97	} VP56RefDc;
98
99	typedef struct VP56Macroblock {
100	uint8_t type;
101	VP56mv mv;
102	} VP56Macroblock;
103
104	typedef struct VP56Model {
105	uint8_t coeff_reorder[64]; /* used in vp6 only */
106	uint8_t coeff_index_to_pos[64]; /* used in vp6 only */
107	uint8_t vector_sig[2]; /* delta sign */
108	uint8_t vector_dct[2]; /* delta coding types */
109	uint8_t vector_pdi[2][2]; /* predefined delta init */
110	uint8_t vector_pdv[2][7]; /* predefined delta values */
111	uint8_t vector_fdv[2][8]; /* 8 bit delta value definition */
112	uint8_t coeff_dccv[2][11]; /* DC coeff value */
113	uint8_t coeff_ract[2][3][6][11]; /* Run/AC coding type and AC coeff value */
114	uint8_t coeff_acct[2][3][3][6][5];/* vp5 only AC coding type for coding group < 3 */
115	uint8_t coeff_dcct[2][36][5]; /* DC coeff coding type */
116	uint8_t coeff_runv[2][14]; /* run value (vp6 only) */
117	uint8_t mb_type[3][10][10]; /* model for decoding MB type */
118	uint8_t mb_types_stats[3][10][2];/* contextual, next MB type stats */
119	} VP56Model;
120
121	struct vp56_context {
122	AVCodecContext *avctx;
123	H264ChromaContext h264chroma;
124	HpelDSPContext hdsp;
125	VideoDSPContext vdsp;
126	VP3DSPContext vp3dsp;
127	VP56DSPContext vp56dsp;
128	uint8_t idct_scantable[64];
129	AVFrame *frames[4];
130	uint8_t *edge_emu_buffer_alloc;
131	uint8_t *edge_emu_buffer;
132	VP56RangeCoder c;
133	VP56RangeCoder cc;
134	VP56RangeCoder *ccp;
135	int sub_version;
136
137	/* frame info */
138	int golden_frame;
139	int plane_width[4];
140	int plane_height[4];
141	int mb_width; /* number of horizontal MB */
142	int mb_height; /* number of vertical MB */
143	int block_offset[6];
144
145	int quantizer;
146	uint16_t dequant_dc;
147	uint16_t dequant_ac;
148
149	/* DC predictors management */
150	VP56RefDc *above_blocks;
151	VP56RefDc left_block[4];
152	int above_block_idx[6];
153	int16_t prev_dc[3][3]; /* [plan][ref_frame] */
154
155	/* blocks / macroblock */
156	VP56mb mb_type;
157	VP56Macroblock *macroblocks;
158	DECLARE_ALIGNED(16, int16_t, block_coeff)[6][64];
159
160	/* motion vectors */
161	VP56mv mv[6]; /* vectors for each block in MB */
162	VP56mv vector_candidate[2];
163	int vector_candidate_pos;
164
165	/* filtering hints */
166	int filter_header; /* used in vp6 only */
167	int deblock_filtering;
168	int filter_selection;
169	int filter_mode;
170	int max_vector_length;
171	int sample_variance_threshold;
172
173	uint8_t coeff_ctx[4][64]; /* used in vp5 only */
174	uint8_t coeff_ctx_last[4]; /* used in vp5 only */
175
176	int has_alpha;
177
178	/* upside-down flipping hints */
179	int flip; /* are we flipping ? */
180	int frbi; /* first row block index in MB */
181	int srbi; /* second row block index in MB */
182	int stride[4]; /* stride for each plan */
183
184	const uint8_t *vp56_coord_div;
185	VP56ParseVectorAdjustment parse_vector_adjustment;
186	VP56Filter filter;
187	VP56ParseCoeff parse_coeff;
188	VP56DefaultModelsInit default_models_init;
189	VP56ParseVectorModels parse_vector_models;
190	VP56ParseCoeffModels parse_coeff_models;
191	VP56ParseHeader parse_header;
192
193	/* for "slice" parallelism between YUV and A */
194	VP56Context *alpha_context;
195
196	VP56Model *modelp;
197	VP56Model model;
198
199	/* huffman decoding */
200	int use_huffman;
201	GetBitContext gb;
202	VLC dccv_vlc[2];
203	VLC runv_vlc[2];
204	VLC ract_vlc[2][3][6];
205	unsigned int nb_null[2][2]; /* number of consecutive NULL DC/AC */
206	};
207
208
209	int ff_vp56_init(AVCodecContext *avctx, int flip, int has_alpha);
210	int ff_vp56_init_context(AVCodecContext avctx, VP56Context s,
211	int flip, int has_alpha);
212	int ff_vp56_free(AVCodecContext *avctx);
213	int ff_vp56_free_context(VP56Context *s);
214	void ff_vp56_init_dequant(VP56Context *s, int quantizer);
215	int ff_vp56_decode_frame(AVCodecContext avctx, void data, int *got_frame,
216	AVPacket *avpkt);
217
218
219	/**
220	* vp56 specific range coder implementation
221	*/
222
223	extern const uint8_t ff_vp56_norm_shift[256];
224	void ff_vp56_init_range_decoder(VP56RangeCoder c, const uint8_t buf, int buf_size);
225
226	static av_always_inline unsigned int vp56_rac_renorm(VP56RangeCoder *c)
227	{
228	int shift = ff_vp56_norm_shift[c->high];
229	int bits = c->bits;
230	unsigned int code_word = c->code_word;
231
232	c->high <<= shift;
233	code_word <<= shift;
234	bits += shift;
235	if(bits >= 0 && c->buffer < c->end) {
236	code_word \|= bytestream_get_be16(&c->buffer) << bits;
237	bits -= 16;
238	}
239	c->bits = bits;
240	return code_word;
241	}
242
243	#if ARCH_ARM
244	#include "arm/vp56_arith.h"
245	#elif ARCH_X86
246	#include "x86/vp56_arith.h"
247	#endif
248
249	#ifndef vp56_rac_get_prob
250	#define vp56_rac_get_prob vp56_rac_get_prob
251	static av_always_inline int vp56_rac_get_prob(VP56RangeCoder *c, uint8_t prob)
252	{
253	unsigned int code_word = vp56_rac_renorm(c);
254	unsigned int low = 1 + (((c->high - 1) * prob) >> 8);
255	unsigned int low_shift = low << 16;
256	int bit = code_word >= low_shift;
257
258	c->high = bit ? c->high - low : low;
259	c->code_word = bit ? code_word - low_shift : code_word;
260
261	return bit;
262	}
263	#endif
264
265	#ifndef vp56_rac_get_prob_branchy
266	// branchy variant, to be used where there's a branch based on the bit decoded
267	static av_always_inline int vp56_rac_get_prob_branchy(VP56RangeCoder *c, int prob)
268	{
269	unsigned long code_word = vp56_rac_renorm(c);
270	unsigned low = 1 + (((c->high - 1) * prob) >> 8);
271	unsigned low_shift = low << 16;
272
273	if (code_word >= low_shift) {
274	c->high -= low;
275	c->code_word = code_word - low_shift;
276	return 1;
277	}
278
279	c->high = low;
280	c->code_word = code_word;
281	return 0;
282	}
283	#endif
284
285	static av_always_inline int vp56_rac_get(VP56RangeCoder *c)
286	{
287	unsigned int code_word = vp56_rac_renorm(c);
288	/* equiprobable */
289	int low = (c->high + 1) >> 1;
290	unsigned int low_shift = low << 16;
291	int bit = code_word >= low_shift;
292	if (bit) {
293	c->high -= low;
294	code_word -= low_shift;
295	} else {
296	c->high = low;
297	}
298
299	c->code_word = code_word;
300	return bit;
301	}
302
303	// rounding is different than vp56_rac_get, is vp56_rac_get wrong?
304	static av_always_inline int vp8_rac_get(VP56RangeCoder *c)
305	{
306	return vp56_rac_get_prob(c, 128);
307	}
308
309	static int vp56_rac_gets(VP56RangeCoder *c, int bits)
310	{
311	int value = 0;
312
313	while (bits--) {
314	value = (value << 1) \| vp56_rac_get(c);
315	}
316
317	return value;
318	}
319
320	static int vp8_rac_get_uint(VP56RangeCoder *c, int bits)
321	{
322	int value = 0;
323
324	while (bits--) {
325	value = (value << 1) \| vp8_rac_get(c);
326	}
327
328	return value;
329	}
330
331	// fixme: add 1 bit to all the calls to this?
332	static av_unused int vp8_rac_get_sint(VP56RangeCoder *c, int bits)
333	{
334	int v;
335
336	if (!vp8_rac_get(c))
337	return 0;
338
339	v = vp8_rac_get_uint(c, bits);
340
341	if (vp8_rac_get(c))
342	v = -v;
343
344	return v;
345	}
346
347	// P(7)
348	static av_unused int vp56_rac_gets_nn(VP56RangeCoder *c, int bits)
349	{
350	int v = vp56_rac_gets(c, 7) << 1;
351	return v + !v;
352	}
353
354	static av_unused int vp8_rac_get_nn(VP56RangeCoder *c)
355	{
356	int v = vp8_rac_get_uint(c, 7) << 1;
357	return v + !v;
358	}
359
360	static av_always_inline
361	int vp56_rac_get_tree(VP56RangeCoder *c,
362	const VP56Tree *tree,
363	const uint8_t *probs)
364	{
365	while (tree->val > 0) {
366	if (vp56_rac_get_prob_branchy(c, probs[tree->prob_idx]))
367	tree += tree->val;
368	else
369	tree++;
370	}
371	return -tree->val;
372	}
373
374	// how probabilities are associated with decisions is different I think
375	// well, the new scheme fits in the old but this way has one fewer branches per decision
376	static av_always_inline int vp8_rac_get_tree(VP56RangeCoder c, const int8_t (tree)[2],
377	const uint8_t *probs)
378	{
379	int i = 0;
380
381	do {
382	i = tree[i][vp56_rac_get_prob(c, probs[i])];
383	} while (i > 0);
384
385	return -i;
386	}
387
388	// DCTextra
389	static av_always_inline int vp8_rac_get_coeff(VP56RangeCoder c, const uint8_t prob)
390	{
391	int v = 0;
392
393	do {
394	v = (v<<1) + vp56_rac_get_prob(c, *prob++);
395	} while (*prob);
396
397	return v;
398	}
399
400	#endif /* AVCODEC_VP56_H */